It's only the biggest whodunit in Philly: Where on earth is the city's missing $26.5 million? And how did Philly lose track of that much money?

It's a question that certified public accountant Kia D. Buckner has been getting a lot lately, and for good reason. City officials hired Buckner, the managing partner of Horsey, Buckner & Heffler LLP, in May to track down the missing funds, and people have been asking her what's going on ever since.

Not to pile on, but I want to know, too. I mean, come on. Even if the unaccounted-for funds are only a small percentage of the city's overall operating budget, I just can't get past the fact that that's still a whole lot of money. That's why I stopped by her firm's Center City office Monday afternoon, to pose a few questions to Buckner myself: Where is the missing money? Have you found it?

"Don't put it like that. In our world, it's 'unreconciled,' " said Buckner, who is heading the audit. "We keep giving this analogy: Just imagine if you did not reconcile your own checkbook for months on end, years on end. It's an accumulation of items that either weren't recorded in your checkbook, were recorded in your checkbook, weren't properly recorded in the bank for one reason, or it's in another account…."

She added, "It's an accumulation of items that we just need to get to the bottom of."

We first learned about Philly's "unreconciled" funds earlier this year after they were flagged in the city's 2017 Comprehensive Annual Financial Report (CAFR), released in February. (Back then, it was $33 million, but some of the money has been accounted for.) Budget hearings followed, along with tough questions about how something like this could happen. One of the chief critics has been Councilman Allan Domb.

"I always felt … this should be done by one of the larger firms, that's totally independent, auditing all of our books and making recommendations," he told me Tuesday. "It shouldn't be [done] by Republicans or Democrats. It should be done by professional, third-party accountants who do large firms to give us a totally unbiased view. It should be one of the Big Four."

Domb's not wrong for wanting the best to help the city figure this out. I don't blame him one bit for wanting to summon one of the big dogs — Deloitte, PricewaterhouseCoopers, Ernst & Young, or  KPMG. But would firms of that size even stoop for a bone this small? It's not likely, says Dan Hood, editor in chief of Accounting Today, a New York City-based trade publication. "It would be a fairly small engagement for them," he told me.

The city contract, which is not to exceed $500,000, was a coup, though, for Horsey Buckner.The firm was the brainchild of Michael G. Horsey, 61, a former managing partner of Mitchell Titus, the nation's largest minority-owned accounting firm. He emerged from retirement to start it along with Buckner, one of his former mentees. The Philly-area natives — he graduated from Roman Catholic High and the University of Pennsylvania's Wharton School, and she from Upper Dublin High and North Carolina A&T University – own 51 percent of HBH. Buckner's former bosses at the 77-year-old mainstream Heffler, Radetich & Saitta control the remaining 49 percent. Buckner is a former principal and head of Heffler's audit department.

Some critics also are giving Horsey, who grew up in North Philly, side-eye for his involvement in the audit because of a past two-year suspension by the U.S. Securities and Exchange Commission. More than a decade ago, Mitchell Titus' audits of the now-defunct MERL Holdings Inc. got flagged for accounting fraud and insider trading.  Horsey insists that's all old news.

"We were ultimately exonerated, but there was no need for me to go back and to get permission to do work with the SEC until I knew I was going to be doing this, and I didn't want that to be a part of my curriculum vitae," Horsey told me.

Look, I don't really care who tracks down the missing funds. All I want is for them to be found — er, "reconciled," as Buckner would say.